BT Certification / Transmitter Characteristics and Antenna Connector

RE: BT Certification / Transmitter Characteristics and Antenna Connector

Andreas — Tue, 23 Oct 2018 11:34:59 GMT

Hi,

By temporary connector I interpret what I tried to say in

[quote user="boan"]Even if there is no coaxial connector on the board, cutting the transmission line and soldering a coaxial cable should be fine. You should run this by your test house though to make sure you are prepared for what they require and prefer to carry out the testing.[/quote]

There are multiple ways of doing this, you could add a coaxial cable or connector manually in your normal design, it does not have to look pretty as long as it is done properly and makes sure the conducted measurement is a good resemblence of the radiated performance in the end-product. Semi rigid cables are very suitable for this.

You can also add space for a coaxial cable connector co-layout with antenna matching network, only actually populated in the devices you use for conducted RF testing. It does not have to be bridged. Bridging could probably be done also, but from my perspective seems to add more complexity than necessary, by adding e.g. a U.FL connector on the RF trace on boards that are used for testing. If you do this you should confirm with the test house that the 2nd layout version is covered by the test also. Layout differences might be more strict for teleregulatory tests though, assuming you intend to test that as well you might want to test only the MP version.

Best regards,

Andreas

RE: BT Certification / Transmitter Characteristics and Antenna Connector

ZAC — Mon, 22 Oct 2018 14:23:56 GMT

Thanks for the reply.

How would you then interpret the wording "temporary connector"?

I assume that for the PHY qualification test, this can be mounted with the condition that it was accounted for in the design for a PCB meant for certification, and then for mass production, a very similar design is used with the only difference that the connector is bridged with regular copper (i.e. not part of the design, as it would have never came into consideration).

However this would mean two layout versions (with exactly one pretty small difference)!

Is that a dilemma, or otherwise according to your experience would still fit to the interpretation of a "temporary connector"?

RE: BT Certification / Transmitter Characteristics and Antenna Connector

Andreas — Mon, 22 Oct 2018 12:04:18 GMT

Hi,

Making sure that each product is compliant to BT requirements is ultimately the responsibility of each respective company selling the product (meaning you in the case of your products). Nordic will not be able to ensure identical characteristics if the board layout differs from our reference design to the degree where it changes the behaviour of the chip.

My understanding is that these measurements are generally performed conducted, though as in the snip from the core spec you attached, there is a possibility to do this conducted. Even if there is no coaxial connector on the board, cutting the transmission line and soldering a coaxial cable should be fine. You should run this by your test house though to make sure you are prepared for what they require and prefer to carry out the testing.

Best regards,

Andreas